Pump mechanism



Aug. 19, 1952 J. E. MCEVOY 2,607,525

h PUMP MECHANISM Fila Oct. 9. 1948 2 SHEETS-SHEET 1 INVENTOR.

. JAMES E. MEVOY FIG. I V W I Aug. 19, 1952 J. E. MCEVOY 2,607,525

PUMP MECHANISM Filed Oct. e. 1948 2 sHEETs-sHEET 2 START OF DISCHARGE FIG. 3

END OF DISCHARGE FIG. 5

INVENTOR.

JAMES E. M EVOY RNEY END OF INTAKE FIG. 6

Patented Aug. 19, 1952 PUMP MECHANISM James E. McEvoy, Cleveland, Ohio, assignor to Bailey Meter Company, a corporation of Delaware Application October 9, 1948, Serial No. 53,671

14 Claims. 1

This invention relates to pump mechanisms, and more particularly to pump mechanisms that are adapted to deliver fluid at a constant volume rate from an intake connection to a discharge connection. V

It is sometimes desirable that a pump mecha nism be provided for pumping fluid ata constant volume rate from a source regardless of changes in back pressure of the discharge end and delivering it to. a point of use in a uniform flow as long as the back pressure remains constant. Where the heating value of a gaseous fluid is to be measured on the basis of heat units per cubic foot of gas supplied from a source, it is necessary that some constant volume pump mechanism be employed. If the temperature and pressure of the gas at the point, of supply are maintained constant, then a cubic foot of such gas will have a predetermined heat: content. By providing a pump mechanism which delivers the gas at a constant volume rate from the source to the point of use, it is possible to determine readily the total heat value of the gas delivered. The pump mechanism should be so designed. as to pump gas from'the sourceat a constant volume rate even thoughthe back pressure at its discharge end'varies. It should also be capable of pumping at a constant volume rate for different densities of the fluid at the intake, and its rate of discharge to the point of use should also be constant. I

An object of my invention is to provide an improved pump mechanism. Another object is to provide a pump'mechanism that is adapted to deliver fluid at a constant volume rate from an intake connection to a discharge connection while the pressure in the latter either remains constant or varies within a predetermined range. Still another object is to provide a pump mechanism for pumping a continuous flow of gaseous fluid at a constant v'olume'rate from asource under for purposes of illustration one form which my invention may assume in practice.

In these drawings: Fig. 1 is a perspective view of my improved pump mechanism.

Figs. 2 to 6 are perspectiveviews of a single pump element ofmy improved mechanism in various positions between the beginning and. end of one complete cycle.

Referring to the drawings it will be notedthat there is shown in Fig. 1a pump mechanism generally designated l including a plurality of tubular pump elements 2, 3 and 4, each bent so that it completes one turn in the path of a helix. A plate 5 is attached to the. ends of each element. as bywelding, for closing the element .andholding the ends in the proper relation relative toeach other. The ends of each of the tubular elements are connected in communication with each other by a U-shaped tube 6 extending downwardly. from the lower side of the element, as shown. The elements are held in spaced parallel relation relative to each other by connectingmembers 8, and a member 9 is shown connected to one of s'aid elements at diametrically opposite points to act as a supporting frame for the connected pump elements. An elongated member Ill extends axially through the pumpelements and is connected to the member 9 so as-to support the elements in positions inwhich the radial distances from the elongated member to the elements are the same at all points along theirlengths. At the lower end of the member ID is a universal joint l2 connecting the member to abase plate l4. Mounted upon a standard 15 extending upwardly from the base plate is a motor l6 which is connected through a gear train I 8 to a shaft [9 carrying a crank arm 20. The upper end of the elongated member ID is connected to the crank arm so that it is moved in a circular path as the shaft [9 is rotated. The shaft [9 is so arranged that its axis is in alignment with the axis of the universal joint I2. It will be appreciated that by this arrangement the member [0 is always held tilted at a. given angle relative to a horizontal plane, and a nutating motion of the pump mechanism is obtained as the upper end of the member ID is swung in a circle by=the crank arm; The lower portioniof the universal joint [2 is held fixed relative to the baseplate seas-to prevent rotation of the member II! on its-own axis. and the upper end of the member II] is loosely, held by the crank arm to permit relative motion between them. 7, v

- The pump elements are so arrangedthat'the ends ofeach are spaced from the ends of the others. Communicating with the ends of each pump element are intake and discharge conduits 22=and 23, the intake conduits being connected to a common conduit 25 andthe discharge conduits being connected to. a common conduit 26.; As shown herein, the intake conduits are connected to the upper ends of the pump elements while the discharge conduits are connected to their lower ends. The motor 16 is operated so that the member ID is swung in a clockwise direction when looked at from above. The discharge ends of the pumpelements arechamfered atZBasshown for reasons that=will be shortly described.

Contained Within each of the pump elements is a volume of liquid 30, such as mercury, and, in a pump mechanism having three pump elements as shown, the volume of liquid is such as to fill each pump element throughout one-third of its length. In Fig. 2 the pump element 2 is shown in a position in which the'liquid is beginning to uncover the intake conduit 22. At the discharge end of this element the liquid moved a short distance into the discharge .conduit 23 but the discharge fluid from the element ahead of the liquid volume wa discontinued as soon as'th'e liquid 'covered'the end of the conduit.

cross sectional areas of the discharge conduits are made small enough so that the movement oi the liquid into them has no appreciable efiect on the discharge 'of fluid. As the element ismoved from the position in Fig. 2 to the posi- 'tion of Fig. 3, the space within the element/communicating with the-intakeis increased'and'fluid to be pumped enters this space from the intake. "In "the, position, of Fig. 3 the discharge conduit isbeginningtobe uncovered so that fluid trapped within the element ahead of the liquid maybe discharged. Movement of the-element from the position of Fig. 3 towardth'e position of Fig.4 results ina-continued increase in the volume of thrspace-at the intake and a decrease of the "space at the discharge end ahead of the liquid volume. "Before reaching the position of Fig.4 theliquid-will have moved completelyo'ut-of the discharge end of the element into the U-tube 6. 'InjFigfB the element 2 has reached a position where the "forward end Of the liquid volume has covered the endo'f the discharge conduit, and thedis'charge of fluid is cut off. As'theposition changes to that offFig. 6, liquid flows from the -discharge'endof the element through the U-tu'be ii to'thfe intake end, and, 'in the position of Fig. '6, theFend-o'fthe intake conduit is covered to trap "theffiuid admitted to the element. In-all positions-of the pum element ithe 'U-tub'e is subetantially filled with liquidsoas to cut .o'ff :communication between the intake and discharge ends.

If *the intake-and discharge pressures arelth'e same, the liquid will stand .in the discharge conduit when in the position i of Fig. I2 at the -sam'e -level-as it does at other points in the element .12. If the discharge pressure .is higher than the im- "ta-he pressure, the liquid-will Ibe'forced backin "the discharge conduit to alower level. By making the-discharge=conduit of small cross sectional area, a forcing Of'the liquid from this iconduit ftothe element will have practically no effect on the level of the liquidin the-latter. If the pump element was made-sothatiits discharge end was of the-same shape asits "intake endand was in alignment therewith, then the level ofthe liquid would-be at the entrance to the discharge con- -duit when-the element was in the position of '2"- and the intake and discharge pressures were equal; Any increase in the discharge pressure wouldrlesu'lt in a forcing of the liquid to a iower "level in the 'discharge end of the element. "The volum'edf the liquid displaced would besconsl der-able and would cause an appreciable increase in the level of the liquid at other points charging fluid at all times.

in the element. This would mean that the beginning of the intake period would be delayed and the space Within which fluid could be trapped would be smaller. The volume of the fluid pumped would drop ofi rapidly with increase in discharge pressure. Locating, the end of the discharge conduit' at a lower level than the intake by dropping the discharge end ofthe element and .chamfering it, as shown, provides for an appreciable change in liquid level at the discharge by changes in back pressure Without affecting the liquid level at other points except by the small amount of liquid displaced from the discharge conduit. This 'has no noticeable effects on the Volume of fluid pumped.

The .chamfering of the pump element at its discharge. end produces another important affect on the operation of the pump mechanism. As the volume of liquid moves through the pump element its forward end lies in a plane cutting the element 'at anangleasshown in Figs. '2 to 6. When the forward end of the liquid volume reaches the discharge end of the element, it first contacts the closed end at the lower sideof the element. If the dis-chargeend was circular, then therewould be a considerable space above the forward face of the liquid filled with fluid that was being pumped. As the position of the elemerit-continued toch'angethe liquid would move up into this space and force ':the fluid therein into the discharge conduit. .It will be appreciated that the rate of fluid discharge would drop continuously from "the time theIliqui-d engages-the "lower edge'o'f 'the:c1os'ed end :until the end'of the element was completely filled with liquid. :33 chamfering the discharge end so that its .shape is :the same as that of .the forward "end of .the -liquid volume, than the discharge :end 501 the element is filled completely vby the liquid as soon as fthe'liquid reachesthi's The vpumpedtfluid is completely discharged :from :the pump element at thisiinstant, and the rate 'o'ffluiddischargefis uniform :during the I'full .period of discharge.

:Since each "of the pump elements :is'only onethird ffilled by the liquid volumethen two-thirds .of the space Iinithe element is. filled'with fluid to be pumped, *and discharge of this fluid takes place "while the volume of liquid moves through an :angle 'of 240?. With the ends of each element spaced from the ends of the other 'elements'there. are always two elements discharging. sIt'will be appreciated that the pump mechanism may be :provided with more or less than three pump elements, if desired. With a'lpump having only two elements, the ends of one-element would .be located from the ends of the other, and-each'would 'be half filled with liquid. -In"thiscaseonly one element would be dischargfing'flllid -.at a time. Just as the-discharge was out on in one 0f the elements, the other ele-' :ment-would be-starting to discharge. By adding *only'one more element, theoutput of the pump .is doubled. If four pump elements were used. they would be arranged so that the points of intake-and discharge were spaced 90 apart, and each element would be /1 filled-with liquid. With this arrangement three elements would -be dis- For each element added the output is increased by the amount-of discharge from one more element. The spacing of the points of intake and discharge and the volume of the liquid used are varied inversely with-.thenumber-of pump .elements.

As a result of my invention there is provided a pump mechanism which takes fluid at a con- "'stant volume rate from an intake connection and will be understood that it may be used as well to pump a liquid provided that the pumped liquid is lighter than the liquid circulated in the elements to produce the pumping action.

While there is described in this application one form which my invention may assume in practice it will be understood that it may be modified and embodied in various forms without departing from the spirit and the scope of the appended claims. a

What I claim as new and desire to secure by Letters Patent of the United States, is:

1; A pump mechanism comprising, in combination, a tubular element conforming to the shape of a helix and extending through an angle of 360, means for closing the ends of said element, passage means for connecting the ends of said element in communication with each other, a volume of liquid partially filling said element, an intake conduit communicating with one end of said element, a discharge conduit communicating with the other end of said element, and means for producing a nutating motion of said element about a vertical axis.

2. The pump mechanism of claim 1 in which said intake conduit communicates with the upper end of said element, and said last mentioned means produces a nutating motion progressing from the intake and along the element toward the discharge end.

3. The pump mechanism of claim 1 in which said passage means comprises a U-tube extending downwardly from the element and having its legs communicating with said ends at a low point on their sides, said intake conduit communicates with the more elevated end of said element, and said last mentioned means produces a nutat ng motion progressing from the intake end along the element toward the discharge end.

4. A pump mechanism comprising, in combination, a tubular element conforming to the shape of a helix and extending through an angle of 360, means for closing the ends of said element, a chamfered portion at the lower of the ends of said element providing. a space conforming to the shape of the end of a liquid volume moving within said element immediately prior to contact between the two, a volume of liquid partially filling said element, passage means for connecting the ends of Said element in communication with each other, an intake conduit communicating with one end of said element, a discharge conduit communicating with the other end of said element, and means for producing a nutating motion of said element about a vertical axis.

5. The pump mechanism of claim 4 in which said intake conduit is connected to the upper end nation, a plurality of tubular elements, each-conforming totheshape'of'a helix and extending through an angle of 360 Ineans for closing the ends of' said elements, means connecting said elements together in spaced axial alignment and with their ends spaced equal angular distances apart, passage means connecting the'ends of each of said elements in communication with 'each other, a volume of liquid partially filling each of said elements, intake conduits communicating with a common source and connected to one endof each of said elements, discharge conduits communicating with a common point of use and connected to theother end of each of said elements, and means for producing a nutating motion of saidconnected elementsabout a vertical axis.

" '7.'The pump mechanism of claim ,6 in which said intakeconduits communicate with the more elevated of the ends of said elements, said discharge conduits communicatewith the lower ends of 'said elements, and said last: mentioned means producesa nutating motion progressing from said upper ends toward said lower ends. I

8. A pump mechanism comprising, in combination, a plurality of tubular elements, each conforming to the shape of a helix and extending through an angle of 360, said elements being spaced along a common central axis, means for closing the ends of said elements, a chamfered portion at the lower end of each of said elements providing a space conforming to the shape of an end of a li uid volume moving within the element immediately prior to contact between the two, a liquid volume partially filling each of said elements, passage means connecting the ends of each of said elements in communication with each other, means connecting said elements together in spaced axial alignment and with their ends spaced equal angular distances apart, intake conduits communicating with a common source and connected to the upper ends of said elements, discharge conduits communicating with a common point of use and connected to the lower ends of said elementsthrough the upper surfaces of said chamfered portions, and means for producing a nutating motion of said connected elements about a vertical axis.

9. The pump mechanism of claim 8 in which said passage means comprises U-tubes connected to the ends of said elements at points on their lower sides and extending downwardly therefrom.

10. The pump-mechanism of claim 8 in which said last mentioned means produces a nutating motion progressing from the intake toward the discharge ends of the elements.

11. The pump mechanism of claim 8 in which said last mentioned means comprises an elongated member extending axially through said connected elements, means connecting said elements to said member so that they are spaced radially equal distances therefrom at all points along their lengths, means supporting one end of said elongated member for pivotal movement in any direction, and means for swinging the other end of said member in a circular path whose center is in vertical alignment with said pivotal supporting means.

12. The pump mechanism of claim 8 in which the discharge conduits are of a small cross sectional area compared to the cross sectional area of said'elements.

13. A pump mechanism comprising, in combination, three tubular elements, each conforming to the shape of a helix and extending through an angle of 360, said elements being spaced along 7 .acommon. :oentral axis, means for closing the ends of said-elements, achamfered poritionat the lower end of each of said elements providing a space conforming to the shape of an end of a :liquidyolume moving within the element immediatelyprior to contact between the 'two, a liquid volume filling each of said elements throughout one-third of .its length, U-tubes connected to the :ends of each of said elements at their lowersides andaextending downwardly therefrom, .means connectingsaidelements together in spaced axial alignment and with their ends spaced 120 apart, intake conduits communicating with a common source and connected to the upper ends of said elements, discharge conduits communicating with a common point .of use and connected .to the .lower ends of said elements through the upper surfaces of :said chamfered portions, (and means for, producing a-nutating motion of .said connected elements about a vertical ,axis.

14. .A pump mechanism comprising,..in combination, a plurality of tubular elements,,each having its longitudinal axis lying in the surface of ya cylinder andVeX-ten'ding through an angle of 360,

means for closing the ends of said elements, pas

sage .,-means for connecting the ends of each of said elementsin communication, means connect- .ing said elements in spaced axial alignment and with their ends spaced equal angular-distances apart, a Volume of liquid partially filling each of said elements, intake conduits communicating with a common source and connected to one .end of eachnof said elements, discharge conduits leading'to .a commonpoint of use and connected to the'other end-of eachof said elements, and means for; producing, a nutating motion of said connected elements about a vertical axis.

o JAMES E. MoEVOY.

REFERENCES CITED 7 The following references are 'of :record :in the file of this patent: UNI'IED STATES PATENTS Number I Name Date 69,40; Bushnell ;Oct. 1, 1867 341,453 Clerc .May 11, 1886 428,638 Schulze-Berge May 27,1890 

